First the red line was wrong.

Then it was right.

But while the red line was moving, NBC viewers of Sunday night's telecast of the New York Giants' 36-31 win over the Philadelphia Eagles may have gotten confused if they weren't paying close attention.

Let's review:

With the Giants trailing, 24-20, New York quarterback Eli Manning released a pass to Kevin Boss on a third-and-10 play from Philadelphia's 20-yard line. A flag was thrown and a call made that Manning was beyond the line of scrimmage when he let go of the ball. The Giants were to be penalized five yards with a loss of down, making it fourth down.

Manning protested immediately and Giants Coach Tom Coughlin challenged the ruling. While replay official Terry McCauley huddled under his hood watching various angles, NBC producer Fred Gaudelli brought up a graphic that was supposed to help clarify the situation for television viewers.

It was a thick red line indicating the line of scrimmage. The line made it appear to some that Manning was fully across the plane of scrimmage when he released the pass, which was completed to the three-yard line. (The NFL rule book states that "the penalty for a forward pass beyond the line is to be enforced from the spot where the ball is released when the passer's entire body and the ball are beyond the line of scrimmage. This includes either when the passer is airborne or touching the ground.")

What wasn't as clear to the casual viewer was that the red line meant nothing to replay officials.

Gaudelli said the red line -- it's blue on Fox NFL telecasts -- is generated by a combination of computer images that are calculated from camera angles and by a GPS system. But it all starts from where Gaudelli tells the computers and the GPS to draw the line.

"What happened," Gaudelli said, "was that I told the group that works with the line to insert the red line over the replay where the center snapped the ball and I just decided to put the line there.

"It's always been clear and we've made clear that our line is never official."

Gaudelli's first red line made it appear to some that Manning had thrown an illegal pass. But replay officials overruled the call on the field and the Giants kept the ball and went on to score a go-ahead touchdown.

Broadcaster Al Michaels, who agreed with the overturning of the play, said he told producer Gaudelli during a time out that NBC's red line was wrong.

"I said, 'Hold on a second, Fred. I think that red line needs to be drawn to where the front of the football was because that's the line of scrimmage."

Gaudelli said he also talked via telephone to Mike Pereira, the NFL's vice president of officiating. While the NBC feed was one of the tools used by replay officials, it is used without any colored lines. Officials are only looking to spot exactly where the down markers are placed.

"Mike told me we had actually drawn our line a little behind the actual line of scrimmage," Gaudelli said. "And I heard the same from Al. So we came back and re-adjusted the red line. No question the officials got it right."

But what viewers saw was a call overturned and then a picture with the new red line indicating a new line of scrimmage, one where Manning's heel was clearly on the line -- making it a legal pass.

While NBC color analyst John Madden was reluctant to change his opinion about whether the officials should have overturned the original call (Madden thought Manning was over the line of scrimmage), even after the new red line was produced, Michaels tried to make certain the audience understood a right decision had been made.

"I can see people might have been confused," Michaels said. "We were saying, 'OK, we've readjusted the red line and now the red line is where it should have been. And I had made the point several times to say that our red line is unofficial. But then Madden and I are joking about it and John says something about the line is readjusted and now I can see he wasn't over the line.

"So that makes it sound like some conspiracy theory if you aren't really paying close attention. But the bottom line is, the right call got made."

Pereira told the Los Angeles Times that McCauley used a live feed of the game to review the play. The picture had a clear view of the sideline marker -- and no red line.

"We don't use the lines -- red, blue, yellow, whatever -- because we know they're inconsistent," Pereira said. "It's not an official designation. It never has been."